Process of attaching metal foil to a surface



lo Drawing.

Patented May 16, 1933 r I UNITED STATES PATENT OFFICE IRVING O. KONEGGER, OI HOUSTON, TEXAS, ASSIGNOR ALUmNUM COMPANY 01' AIERIOA, OF PITTSBURGH, PENNSYLVANIA, A CORPORATION OF PENNSYLVANIA PROCESS OF ATTACEING METAL FOIL,T 'A SURFACE This invention relates to the coating of articles with metal foil, and especlall to processes of attaching foil tothe art1c e to be coated.

Metal foil possesses var ous advantages as a coating for articles of widely dlverse character and use. One advantage 1s due the flexibility of metal foil, which permlts its 1ntimate application to irregular surfaces, corners, and the like; for example, in coverin shingles, pavements, contamers, and ot er objects. Metal foils generally possess a bright surface, so that they have heat reflecting properties which render such coatings valuable for 081138.111 urposes. Aluminum foil is particularly esirable for these purposes, and, in addition tOthQPIZOPGI'lGIGS generally possessed by metal .foil, 1ts high thermal expansivlty adapt'sit'as a for articles which are sub ect to expansion and contraction. I Also, aluminum. foil. is resistant to weathering and other chemical influences, such as acids.

Prior to my invention, no pract cal means had been available for satisfactorily attaching metal foil to the wide yariety of mate: rials of varying compos tlon and surface character which it is desired to coat. The general practice in attaching a materlal' 1n sheet form to another article is to use liquid adhesives, which, for various reasons, are undesirable and unsuited for the purpose. Their proper use requires skilled judgment in deciding when the adheslve has assumed the proper consistency, or adhes1 veness, 'after being applied to the foil, and the quahty of coatlng therefore depends u on a personal element. There is also the anger 1n usmg such adhesives that air pockets will trapped under the foil, thus reducing the eflicacy of the coatin Further ob ections to such prior procedures arise from the necessity for using such liquid adhesives where the coating operation is effected, and this is particularly disadvantage- Application filed Kay 12, 1931. Serial No. 586,957,

covering placed with the asphaltfilm directly ous in field operations. In all such rocedures, involving manual application of the adhesive, non-umform application of the adhesive generally results, with uneconomical consequences. Also, where heated adhesives are used there is the constant danger of injury to the operators. More serious objections, however, are due to the li htness and flexibilit of the foil, which ma e its handling di cult. Thus, air currents tend to not easy to obtain smooth and tightly adherent coating. Especially is this true in" outdoor work when wind is blowing, under which conditions-the foil may be torn easily. All of these factors have militated against successful foil coating prior to this'invention.

It is among the objects, of this invention to provide a process of coating surfaces with metal foil which is simple, a plicable to the coating of a great variety 0 surfaces, effective under 'widely difl'ering conditions,

economical, does not require. cumbersome apparatus or skilled manipulation, and overcomes many of the disadvantages of prior methods of coating with metal foil.

This invention is predicated on my discovery that theseand other objects are accomplished by applying a layer of asphalt to one side of a sheet of foil, drying or congealing the film, and then pressing the coated side directly against the surface-to be covered 1) applying eat and dpressure through the foi n the preferre embodiment of the invention foil is prepared for use by passing it over a roller running in molten asphalt, to apply a layer of asphalt to one side of the foil. The asphalt film is cooled quickly to congea'l it. and the thus-coated foil is coded, or otherwise packaged, and kept int-his condition until needed.

In the use of this material the foil is against a surface to be foiled, whether of wood, glass,

55 cause wrinkling as it is applied, so that it is i metal, composition, concrete or other ma terial, and heat and pressure are applied through the foil. Under the influence of the heat the asphalt is softened, and the pressure applied to the foil forces it into intimate contact with the surface being coated. The asphalt flows into the surface irregularities, and upon again cooling good adhesion results. The heat and pressure may be applied simultaneously by any suitable means, for instance by a hot smoothing iron or roller.

In the preferred embodiment of the inven:

tion bright aluminum foil is used. The asphalt coating ma be thin, the thickness being, of course, ependent upon the character of the surface to be coated. For example, rough surfaces usually require heavier coatings than do smooth surfaces.

The thinness of the foil and its high heat conductivity insure rapid softening of the asphalt coating, permitting it to be pressed readily into contact with the surface, so that the laying operation is rapid. Because 0 its especially high thermal conductivity, aluminum foil is particularl efiicacious from this standpoint. In addition to its pro erty of congealing and being softened under cat, which permits preparation of the coated foil away from its field of use, desirable as a binder because it wets an adheres to surfaces differing widely in character. The method thus provided is advantageous also because it minimizes the hazard of air pockets, which are commonl encountered in applying coatings with iquid adhesives. Such air pockets tend to cause peeling, and to weaken the coating.

A particular advantage of the invention results from congealing of the asphalt coating. This stiifens the foil and makes it much more convenient to handle under widely varying conditions than foil not so provided with a hardened asphalt coating. For instance, the foil does not tend to wrinkle when applied to the surface to be coated, so that it is easier'to obtain unwrinkled tight coatings of satisfactory quality than where the foil is not coated, or where liquid adhesives are used. Particularly, it makes the foil more amenable to use for outdoor coating operations, and reduces damage through tearing.

Both the asphalt and the foil repel water, so thatv these coatings are useful in preventing passage of water through the coated article. This quality may be useful, for example, in conserving moisture, as in curing concrete; and this property is enhanced by the heat-reducing properties of the foil, particularly bright aluminum foil, which tend to lower the tempe'ratureof the object beneath it. Moreover, under extremes of temperature the asphalt film possesses su cient plasticity for the foil to adjust itself without buckling or cracking, as in contraction .ing the coating.

f burned by hot asphalt d invention may be practiced otherwise than as and expansion of tanks or pavements. And on expansion of the underlying structure, as on swelling of wood, there is sufiicient elasticity to afford adjustment of both the asphalt film and the metal foil without damag- A further advantage of this coating is that over long periods of time the attaching asphalt, even though only a film, retains its valuable qualities.

Further advanta es of the invention are that the foil may e prepared for use and stored until needed, without deterioration of the adhesive. This reduces the equipment needed at the place of use, and particularly the human element is reduced greatly, because the necessity for judging as to the proper condition of adhesive when applying coating is dispensed with, it being necessary only to apply enough heat and pressure to cause the desired adherence. Moreover, economies result from the uniformity of the asphalt coating obtained by mechanical application, and the danger of operators being adhesives is minimized,

According to the provisions of the patent statutes, I have explained the principle of my invention, and have described what I now consider to represent its best embodiment. However, I desire to have it understood that, within the scope of the appended claims,-the

specifically described. I claim:

1. The process a surface, comprising apply ng a layer 0 asphalt to one side of a sheet of foil, congealing said layer to harden it and stiffen the foil, placing in direct contact with a surface to be covered by said foil, and applying heat and pressure through the foil to soften and press said of attaching metal foil to coating into adherent contact with said surface.

2. The process of attachin to a surface, comprising app ying a layer 0 asphalt to one side of a sheet .of aluminum foil, congealing stiffen the foil, lacing the coated side of the stifiened foil in direct contact with said surface, and applying heat and pressure through the foil to soften and press said coating into adherent contact with said surface.

3. The pro ,ess of attaching aluminum foil to a surface, comprising app ying a layer of liquefied asphalt to one side of aluminum foil, congealing said layer to harden it and stifien the foil, placing the coated side of the stiffened foil in directcontact with said surface, applying a heated metallic presser element to the exposed surface 0 the foil to soften said asphalt and press it into intimate contact with the surface to cause adherence of the foil thereto.

4.. The process of attachin aluminum foil to a substantially rigid surf ace, comprising aluminum foil the coated side of the stiffened foil said layer to harden it and applying a layer of asphalt to one side of a sheet of aluminum foil, congealing said layer to harden it and stiffen the foil, placing the coated side of the stiffened foil in direct contact with said substantially ri 'd surface, and applying heat and ressure t rough the foil to soften said aspha t and press it into adherent contact with said surface to cause adhero ence of the foil thereto.

5. As a new article of manufacture for coatin surfaces, aluminum foil with a layer of as t con led on one side thereof, where y the fox is stifiened.

In testimony whereof, I sign my name.

IRVING C. HONEGGER. 

